Anti-counterfeit technologies known include holograms, watermarks, a latent image pattern, pearl ink, luminescent ink, intaglio printing, and micro-characters. Among them, since imitation and copy are unlikely to occur when application of anti-counterfeiting technology is not easily verified, attention has been paid to anti-counterfeiting technology utilizing information which cannot be visually (in naked eye) verified. However, in recent years printing technology has been developed enabling to print a high-resolution image so that even when the location of information which cannot be visually verified is specified, there is a problem that imitation or copy is likely to occur.
Therefore, anti-counterfeit technology using fine particles has been proposed. The fine particles are referred to as a tracking taggant (tracking additive). Fine particles having information identifiable by magnification are known, and for example, fine particles having symbols such as letters, numerals, signs, and marks and special shapes and fine particles in which multilayers of colored thin films are laminated were proposed (For example, see Patent Literatures No. 1 to 4.) In fine particles having symbols or special shapes, authenticity can be judged by magnifying the symbol or special shape for identification. In fine particles in which multilayers of colored thin films are laminated, authenticity can be judged by magnifying the color pattern of multilayered films for identification. In such anti-counterfeiting technology using fine particles, verification of fine particles themselves is difficult making imitation and copy difficult, thereby expressing excellent anti-counterfeiting effects.